Storage-stable moulding and coating compositions

ABSTRACT

1. A CURABLE STORAGE-STABLE COMPOSITION COMPRISING A MIXTURE OF (A) AN ESSENTIALLY LINEAR POLYESTER OBTAINED BY CONDENSATION OF A POLYOL WITH AN ACID COMPONENT CONTAINING AN A,B-UNSATURATED DICARBOXYLIC ACID OR ITS ESTER OR ITS ANHYDRIDE OR A MIXTURE THEREOF, SAID POLYESTER CONTAINING A CONVENTIONAL STABILIZER; (B) A VINYL MONOMER COPOLYMERIZABLE WITH THE POLYESTER; (C) AN A-HYDROXY KETONE OR A BENZOIN ETHER OF A PRIMARY ALCOHOL; OR A MIXTURE THEREOF AND; (D) AT LEAST ONE AT LEAST DIBASIC ACID OF PHOSPHOROUS HAVING P-OH- ACIDITY OR PARTIAL ESTERS THEREOF CONTAINING AT LEAST TWO (P) -OH GROUPS.

United "States Patent US. Cl. 260-863 13 Claims ABSTRACT OF THEDISCLOSURE A curable storage-stable composition comprising a mixture ofa polyester having a,[3-unsaturated dicarboxylic acid radicals, a vinylmonomer copolymerizable with this polyester, an m-hydroxyketone and/orbenzoin ether of a primary alcohol and a dibasic acid of phosphorushaving P-OH acidity or partial esters thereof, containing at least two(P)OH groups.

This is a continuation-in-part of copending application Ser. No.273,507, filed July 20, 1972, and now abandoned.

The invention relates to the stabilization towards storage of a moldingand coating composition based on a mixture of a polyester havingu,;8-unsatura-ted dicarboxylic acid radicals and being stabilized in theusual manner, a copolymerizable vinyl monomer, a-hydroxyketones and/ orbenzoin-ethers of primary alcohols, and at least one dibasic and/or morethan dibasic acid of phosphorus having POH acidity or partial estersthereof containing at least two (P)OH groups, as additional stabilizers.

Mixtures of polyesters having a,fi-unsaturated dicarboxylic acidradicals, copolymerizable vinyl monomers, a-hydroxyketones and/orbenzoin-ethers of primary alcohols are known. If aliphatica-hydroxyketoues are used according to DAS (German PublishedSpecification) 1,150,805, the mixtures can be cured thermally with orwithout the addition of peroxide, or can, in combination with compoundsof vanadium, acids of phosphorus having P--OH acidity or partial estersthereof and organic peroxides according to our copending PatentApplication P 21 36 493 (Le A 13,864) be used at room temperature,whilst when aromatic substituted oc-hYdfOXYkEtOHES are used, such asbenzoin or benzoin-ethers of primary alcohols, the mixtures can be curedby irradiation with UV- light, to give moldings of coatings.

The known mixtures mentioned above generally suffer from thedisadvantage of not being sufficiently storagestable even in the dark(DAS, i.e. German Published Specification 1,694,149

This invention now provides a curable storage-stable compositioncomprising a mixture of (A) a usually stabilized polyester havingage-unsaturated dicarboxylic acid radicals;

(B) a vinyl monomer copolymerizable with the polyester;

(C) an u-hydroxy ketone and/or a benzoin ether of a primary alcohol; and

(D) at least one at least dibasic acid of phosphorus having POH acidityor partial esters thereof, containing at least two (P)OH groups.

The composition preferably contains 0.0005 to 1 wt. percent, morepreferably 0.001 to 0.01 wt. percent of phosphorus as component D, andpreferably 0.001 to 10 wt. percent, more preferably 0.005 to 3 wt.percent of 3,845,162 Patented Oct. 29, 1974 component C. Thesepercentages are by weight referred to in total composition.

The invention also provides a process for coating a substrate or amolding comprising curing the composition of the invention either as alayer on the substrate or in a mold.

The acids of phosphorus having PO-H acidity or partial esters thereofcontaining at least two (P)OH groups, used as component D function asadditional stabilizers to increase the storage-stability of thecompositions in the dark. Using the present invention, compositions asdefined above can be formulated which possess such storage stability inthe dark that they meet the requirements of industry and can be reliablyprocessed on streamlined molding and coating installations without thedanger of a premature uncontrolled polymerization.

Being metal-free compounds, the additional stabilizers described aboveas component D neither discolour the cured or uncured compositions, norretard the curing, to any significant extent.

Further, the stabilizers used according to the invention remove thenecessity for the component C to be stored separately from the polyestersolution.

Whilst esters of phosphoric acids have already been used in polyestercoating compositions combined with metal accelerators and peroxides inorder to improve the colour of the cured products, the special acids ofphosphorus according to the invention are new as additional stabilizersfor the said mixtures.

Polyesters containing a,,BllI1SatUIat8d dicarboxylic acid radicals, asused in the compositions of the invention, are as usual those which areproduced by polycondensation of a e-unsaturated dicarboxylic acid, forexample, maleic acid, fumaric acid, mesaconic acid, itaconic acid,citraconic acid and/ or dimeric (meth) acrylic acid, or their esters oranhydrides or their mixtures, with optionally unsaturated polyhydricalcohols, such as ethylene glycol, 1,2-propanediol, 1,4-butanediol,1,4-butene-(2)-diol, 1,6- hexanediol, diethylene glycol,polyalkylene-glycol-ethers, bis-p-hydroxyalkyl-ethers of aromaticdihydroxy compounds, for example 2,2-bis(4-j8-hydroxy-alkoxyphenyl)-alkanes and -cycloalkanes, xylylene glycols, 1,3-dimethylolcyclobutane,quinitol and 2,2-bis-(hydroxycyclohexyl)- alkanes and -cycloalkanes,optionally with the addition of other dicarboxylic acids, such asophthalic acid, iso phthalic acid, terephthalic acid, tetrahydrophthalicacid, hexahydrophthalic acid, tetrachlorophthalic acid,endomethylenetetrahydrophthalic acid,hexachloroendomethylenetetrahydrophthalic acid, succinic acid, glutaricacid, adipic acid and pimelic acid or monocarboxylic acids, such asacrylic acid and methacrylic acid, or other monohydric or polyhydricalcohols, such as glycerine, trimethylolethane, pentaerythritol, allylalcohol and partial ethers of monohydric and polyhydric alcohols(compare, for example, the book by I. Bjorksten et al. Polyesters andtheir Application, Reinhold Publishing Corporation, New York, 1956),optionally in combination with compounds which possess the allyl-etherconfiguration and can be built into the polyesters or be mixed into thesolutions, such as, for example, Sm-unsaturated alkyl ethers, such asallyl, methallyl, ethallyl, chloroallyl and crotyl ethers of thepolyalcohols already mentioned, or in combination with methylolcompounds which are derived from urea or melamine and are etherifiedwith pa -unsaturated alcohols, such as methylolglyoxalureins ormethylolmelamines; reaction products of polyhydric alcohols withacrolein belong to this category.

Before or after the esterification reaction by which the polyester A isproduced, customary stabilizers such as phenol, guaiacol, hydroquinone,pyrocatechol, resorcinol, pyrogallol, phloroglucinol, toluhydroquinone,benzoquinone,

3 naphthol, naphthoquinone, 2,5-di-tert.-butyl benzoquinone, chloranil,tert.-butyl pyrocatechol, and the alkyl, halogen, and nitro derivativesof said compounds can be added, in the customary amounts, to theesterification batch for stabilizing the unsaturated polyester in theusual manner.

Copolymerizable vinyl monomers are for example sty rene,nuclear-substituted styrenes, divinylbenzene, acrylic and methacrylicacid or their esters or amides, esters of vinyl alcohol or allylalcohol, and vinylketones.

A suitable component C may be any a-hydroxy-ketone, such as compounds offormula OOH R R being the same or different, or forming a -8 memberedring together with the two C-atoms of the u-hydroxy-ketone group;

(a) R R representing an aliphatic radical with 1-30 C- atoms, thisaliphatic radical being an alkyl group, in case substituted by one ormore nitro-, hydroxy-, halogen-, amino- (in case substituted by 1-2alkyl radicals with 1-6 C-atoms), alkoxy- (1-12 C-atoms), methoyloland/or methylol-ether group and/or aromatic group 6-12 C-atoms);

(b) representing a cycloaliphatic radical (5-7 rings), in

case substituted by one or more nitro-, hydroxy-, halogen-, amino- (incase substituted by 1-2 aliphatic radicals with 1-6 C-atoms),methyloland/or methylolether-, alkyl- (1-12 C-atoms) and/or alkoxy group(1-12 C-atoms);

(c) representing an aromatic radical (1-16) C-atoms), in

case substituted by aromatic radicals (1-12 C-atoms) or in casesubstituted by 1-4 alkyl- (1-10 C-atoms), 1-3 nitro-, 1-4 halogen-, 1-4methyloland/ or methylolether groups, 1-4 alkoxy (1-12 C-atorns) groups;such components D being e.g. acetol, dihydroxy acetone, benzoin,ot-hydroxymethyl benzoin and nuclear-substituted benzoins,u-hydroxycyclopentanone, a-hydroxycyclohexanone.

(d) R representing hydrogen, an alkyl group (1-12 C), a

methylol or methylolcther group.

A suitable component C may also be any ether of primary alcohols (theprimary alcohol may contain 1-18 C atoms) of the benzoins listed aboveunder (c); the alcohol component of said esters may be an alkanol with1-24 C- atoms, a cycloalkanol with 5-24 C-atoms, an aryl alcohol with5-24 C-atoms, an aralkyl alcohol with 6-24 C-atoms and the nitro-,halogenand alkoxy- (with 1-12 C-atoms) substituted derivatives thereof;e.g. benzoin methyl ether, -ethyl ether, -n-propyl ether and -n-butylether or their nuclear-substituted derivatives, such as 4,4-dimethyl-,4,4- dichloroand 4,4-dimethoxy-benzoin ethyl ether.

Some u-hydroxy compounds are in the form of crystalline dimers whichhowever again decompose into the monomers on fusion and canadvantageously be incorporated in this form into the mixtures.

Suitable additional stabilizers for use as component D are: dibasicand/or more than dibasic acids of phosphorus having POH acidity such asphosphoric acid, pyrophosphoric acid, polyphosphoric acid, phosphorousacid and the possible dibasic and/ or more than dibasic partial estersof the said acids, for example the monomethyl, monoethyl, monopropyl,monoisopropyl, monobutyl, monoisobutyl, mono-oxalkyl, monohalogenalkyl,monocyclohexyl, monophenyl esters of phosphoric acid, the correspondingmonoesters and/or diesters of pyrophosphoric acid and the correspondingdibasic and/or more than dibasic acidic esters of polyphosphoric acid,partial dibasic and/or more than dibasic acidic salts of the said acidsand/or their esters, such as, for example, the dibasic acidic ammoniumsalt of a partial pyrophosphoric acid ester or the dibasic or the morethan dibasic acidic ammonium salt of a partial polyphosphoric acidester.

The molding and coating composition according to the invention mostpreferably contain the said additional stabilizers in amountscorresponding to about 0.002% by weight of phosphorus since at thisconcentration optimum storage stability is in most cases found.

The additional stabilizers are advantageously added to the polyestersolutions as produced. They can however also be added at the start ofthe esterification by which the polyester is produced or during themanufacture of its melt; this procedure however leads to a loss inactivity, which can in turn be compensated for using a correspondinglyhigher amount.

The storage-stable molding and coating compositions claimed can be curedthermally with or without addition of peroxide, or, in combination withcompounds of vanadium, acids of phosphorus having POH acidity andperoxides according to our copending Patent Application P 21 36 493 (LeA 13,864), can be cured at room temperature or, when usingaromatic-substituted a-hydroxyketones, such as benzoin or benzoin ethersof primary alcohols, can be cured by irradiation with UV-light, Withoutadverse discolorations which might be attributable to the additionalstabilizer.

Of course, pigments, dyestuffs, fillers, glass fibres or textile fibres,agents for conferring thixotropy, UV-absorbers, waxes, parafiin,smoothing agents and levelling agents and the like can also be added tothe composition.

Examples In the examples which follow, an unsaturated polyester is used,the composition of which in parts by weight is given below. It ismanufactured in a known manner by melt condensation until the viscosityand acid number mentioned below are obtained, and is dissolved instyrene to give a 65% strength solution. Before dissolving it,toluhydroquinone is added.

1. Maleic anhydride: 588 g.

2. Phthalic anhydride: 592 g.

3. 1,2-propylene glycol: 798 g.

4. Toluhydroquinone: 0.36 g. Characteristics of the styrene solution:

Solids content: 65%

Viscosity (20 C.) 1,800 cp.

Acid number: 21

1 Measured in the falling ball viscometer according to Hiippler.

In all the examples which follow, the polyester solution is mixed withthe tabulated percent by weight, relative to polyester solution, ofa-hydroxyketones or benzoin ethers of primary alcohols and withdifferent amounts of the solution of additional stabilizer. Thesolutions of additional stabilizer contain the listed dibasic and/ormore than dibasic acids of phosphorus dissolved in butyl acetate, ineach case in an amount corresponding to 7% by weight of phosphorus.

Additional Stabilizer Solution:

A: Polyphosphoric acid in butyl acetate, 7

B: Phosphorous acid in butyl acetate, 7

C: Phosphoric acid in butyl acetate, 7

D: Pyrophosphoric acid in butyl acetate, 7

E: Dibutyl pyrophosphoric acid ester in butyl acetate, 7 Comparisonsolutions, not claimed:

F: Diisooctyl phosphate acid in butyl acetate, 7

G: Dibutyl phosphite acid in butyl acetate, 7

H: Tris-chloroethylphosphite acid in butyl acetate, 7

Determination of the storage stability in the dark 35 g. portions of themixture are filled into 50 ml. powder jars with Screw lids withoutgaskets, the lid is screwed on and the jar is stored in the dark at 60C. At certain intervals of time, the jar is slightly tipped to ascertainwhether the sample has gelled. The values quoted are 6 In the exampleswhich follow, curing reactions are carried out which show that theadditional stabilizers do not impair the curing of the mixtures.

average values of at least 3 samples. 5 Example 25 The quantitative datagiven in the tables are percentages M f t f a putty by mixing the f llwing by weight relative to the polyester solution. In Table I stituents:below, various additional stabilizer solutlons of the same 3000 g ofpolyester solution containing 01% by weight phosphorus content (7% byweight) are compared with 10 f additional Stabilizer solution A oneanother. 6.00 g. of styrene TABLE 1' Example number 1 2 3 4 5 1a 2a 3a4a Benzoin 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Additional stabilizersolution:

B "0'0' c 0.025 D E .025 Comparison solutions:

F 0.025 G 0.025 H 0.025 Storage stability in the dark at 60 C.

(days) 7 8 4 i 2 1 2 1 2 1 2 1 Hours. The amounts listed here arespecified in grams.

In Table I, the Examples 1 to 5 clearly show the effect 28.70 g. of talcof the additional stabilizers according to the invention in comparisonto Examples 1a to 4a.

In Tables II and 'III below, the amounts of the additional stabilizersolutions A and B are varied. The stabilizing effect manifests itself inthis case particularly clearly in the optimum Examples 9 and 16, inwhich the storage stability in the dark at 60 C. is raised from 2 hoursto 6 days.

1.60 g. of titanium dioxide RKB (Bayer) 28.70 g. of asbestine 4.80 g. oflithopone 0.18 g. of a-hydroxycyclohexanone, fused 3.00 g. of methylethyl ketone peroxide, 50% strength The same composition as above, butwith a polyester solution which does not contain any additionalstabilizer,

TABLE II Com- Example parison 6 7 8 9 10 11 12 Benzoin 1. 0 1. 0 1. 0 1.0 1. 0 1.0 1. 0 l. 0 Additional stabilizer soluon A None 0. 010 0. 0250. 05 0. 1 0. 5 1. 0 2.0 Storage stability in the dark at 60 C. (days) 25 3 5 6 5 3 2 1 Hours. The amounts listed here are specified in grams.

TABLE III Com- Example parison 13 14 15 16 17 18 19 Benzoin 1. 0 1. 0 1.0 1. 0 1. 0 1. 0 1. 0 1. 0 Additional stabilizer solution None 0. 0100.015 0.025 0. 05 0. 25 0.5 2.5 Storage stability in the dark at 60 C.(days) 1 2 4 1 4 6 4 2 15 1 Hours.

Table IV compares the stabilizing action of the additional is used asthe comparison example. For curing, 3 g. of a stabilizer solution A forvarious mixtures containing a- 60 solution, containing 0.5% by weight ofvanadium, of

hydroxyketones or benzoin ethers of primary alcohols. Examples 23, 24and 25 additionally contain toluhydroquinone.

TABLE IV V 0 in acidic phosphoric acid mono-n-butyl ester and tolueneare worked into the putties and the compositions are spread approx. 1mm. thick onto iron sheets.

Example number 20 20a Additional stabilizer solution A ToluhydroquinnmBenzoin Benzoin ethyl ether A notni n Acetol.

Dihydroxyacetone A-Hydroxyoyelohexanone Storage stability in the dark at0. (days)..

1 Hours. The amounts listed here are specified in grams.

In the curing reaction of lacquer films shown below, the curing processis again found not to be impaired by the additional stabilizer.

Method 8.3 g. of polyester solution containing 0.1% by weight ofadditional stabilizer solution A, 1.7 g. of styrene, 0.2 g. of astrength by weight paraffin solution in toluene (paraflin of meltingpoint 51-53 C.) and 0.2 g. of benzoin ethyl ether are mixed in a testtube. The same mixture, with a polyester solution without additionalstabilizer, serves as the comparison example. The solutions are spreadas 250 1. thick films on glass plates by means of a filmspreadinginstrument and exposed to the radiation of a fluorescent tube (Osram Llamp for copying purposes, 40 watt, 97 cm. length) at a distance of 10cm.

We claim:

1. A curable storage-stable composition comprising a mixture of (A) anessentially linear polyester obtained by condensation of a polyol withan acid component containing an c p-unsaturated dicarboxylic acid or itsester or its anhydride or a mixture thereof, said polyester containing aconventional stabilizer; (B) a vinyl monomer copolymerizable with thepolyester; (C) an a-hydroxy ketone or a benzoin ether of a primaryalcohol; or a mixture thereof and; (D) at least one at least dibasicacid of phosphorus having POH acidity or partial esters thereof containing at least two (P)OH groups. 2. The composition of claim 1 whichcontains 0.0005 to 1 wt. percent of phosphorus as component D.

3. The composition of claim 1 which contains 0.001 to 0.01 Wt. percentof phosphorus as component D.

4. The composition of claim 1 which contains 0.002 wt. percent ofphosphorus as component D.

5. The composition of claim 1 which contains, as component D, phosphoricacid, pyrophosphoric acid, polyphosphoric acid, phosphorous acid, or themonomethyl, monoethyl, monopropyl, monocyclohexyl or monophenyl ester ofphosphoric acid, or a corresponding monoester or diester ofpyrophosphoric acid or a corresponding dibasic or more than dibasicacidic ester of polyphosphoric acid, or an acidic dibasic or more thandibasic acidic salt of one of these acids or partial esters.

6. The composition of claim 1 which contains 0.001 to 10 wt. percent ofcomponent C.

7. The composition of claim 1 which contains 0005 to 3 wt. percent ofcomponent C.

8. The process of coating a substrate or a molding comprising curing thecomposition of claim 1 either as a layer on the substrate or in a mold.

9. The process of claim 8 in which the curing is induced by heat.

10. The process of claim 8 carried out without heating in the presenceof a compound of vanadium, an acid of phosphorus having PO-I-I acidityor a partial ester of such an acid, and a peroxide.

11. The process of claim 8 in which component C of the composition is abenzoin or a benzoinether of a primary alcohol or derivatives thereofand curing is carried out under the influence of ultraviolet light.

12. Articles having coatings manufactured by the process of claim 8.

13. Molded article manufactured by the process of claim 9.

References Cited UNITED STATES PATENTS 3,031,301 4/1962 Agens 96-273,079,363 2/1963 Koch et al. 260-863 3,238,274 3/1966 Allan 260-8633,582,487 6/1971 Fuhr et al 204-15915 3,607,693 9/1971 Heine et al204-15915 3,699,022 10/1972 Behrens et al. 204-15915 3,721,723 3/ 1973Heidel 260-865 FOREIGN PATENTS 1,046,874 11/1953 Germany.

1,098,712 12/1956 Germany.

1,156,460 6/ 1969 Great Britain.

WILLIAM H. SHORT, Primary Examiner E. A. NIELSEN, Assistant ExaminerU.S. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patent 3,845,162'Dated October 29, 1974 "Bernhard Hess, Karl Raichle, Hans Rudolph andKarl Fuhr Inventofls) It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Col. 1, lines and 5, should read--- Bernhard Hess, Kapellen near Moers,Hans Rudolph and Karl Raichle, Krefeld Bockum and Karl Fuhr, Kreline 48,"used" should read -cured-.

Signed and sealed this 6th day of May 1.975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officerand Trademarks

1. A CURABLE STORAGE-STABLE COMPOSITION COMPRISING A MIXTURE OF (A) AN ESSENTIALLY LINEAR POLYESTER OBTAINED BY CONDENSATION OF A POLYOL WITH AN ACID COMPONENT CONTAINING AN A,B-UNSATURATED DICARBOXYLIC ACID OR ITS ESTER OR ITS ANHYDRIDE OR A MIXTURE THEREOF, SAID POLYESTER CONTAINING A CONVENTIONAL STABILIZER; (B) A VINYL MONOMER COPOLYMERIZABLE WITH THE POLYESTER; (C) AN A-HYDROXY KETONE OR A BENZOIN ETHER OF A PRIMARY ALCOHOL; OR A MIXTURE THEREOF AND; (D) AT LEAST ONE AT LEAST DIBASIC ACID OF PHOSPHOROUS HAVING P-OH- ACIDITY OR PARTIAL ESTERS THEREOF CONTAINING AT LEAST TWO (P) -OH GROUPS. 